Astronomy & Astrophotography Calculators
Explore telescope optics and sky geometry with clear formulas, explicit measurement conventions and exportable results. Choose a completed tool below to calculate your setup or angular measurements.
Understand your telescope setup
Telescope Optics
Calculate magnification, visual or camera field, exit pupil and ideal Rayleigh separation. Keep each quantity and its assumptions distinct.
4 calculators
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Telescope Magnification Calculator
Calculate telescope magnification from focal lengths and an optical multiplier. Compare two eyepieces with a chart, clear formulas and exportable results.
- Open
Telescope Field of View Calculator
Estimate visual eyepiece field or calculate rectangular camera coverage from sensor dimensions and effective focal length, with a framing diagram.
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Telescope Exit Pupil Calculator
Find exit-pupil diameter from telescope aperture and magnification, or solve for the power that produces an entered target pupil.
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Telescope Resolution Calculator
Calculate the theoretical Rayleigh angular separation from clear aperture and wavelength, with explicit diffraction and small-angle assumptions.
Understand your telescope setup
Imaging Scale
Translate camera pixel pitch, effective focal length and square binning into angular sampling per output pixel.
1 calculators
Understand your telescope setup
Sky Geometry
Convert a transverse physical size and distance into an angular span with explicit flat-plane geometry.
1 calculators
Choose the quantity you need
Magnification describes nominal image enlargement from focal lengths. Field of view describes angular coverage, using an approximate visual formula or a rectilinear camera model with a framing diagram.
Exit pupil describes the nominal beam diameter from aperture and power. Its inverse mode finds magnification for a target pupil you supply; no universal preferred pupil is assumed.
Resolution provides the ideal Rayleigh separation for an unobstructed circular aperture at an entered wavelength. Angular size instead uses a flat transverse object's diameter and distance; it does not infer cosmological distance or a spherical silhouette.
Each completed tool includes worked examples, linked method sources and downloadable results. Unit selectors convert existing measurements. The formulas describe specified geometry, while observing conditions and optical quality still affect the actual view.